Time delay switch having pneumatically delayed disconnection means



Feb. 7, 1967 R. ANSCHUTZ 3,303,297

TIME DELAY SWITCH HAVING PNEUMATIC-ALLY DELAYED DISCONNECTION MEANS Filed Nov. 30, 1964 Q I I a A E 4 i vm j A? Q, & m

A TTOEIVEXS.

slide into the disconnect position.

United States Patent Ofiice 9 Claims. in. zoo-s4 This invention relates in general to electrical switch construction, and in particular to a new and useful time delay switch having pneumatically delayed disconnection means.

The present invention is particularly related to an electrical time switch having a pneumatically delayed prolonged resetting particularly for use with auxiliary heaters in motor vehicles. The expensive pneumatic retarding mechanisms for resetting time switches are known which comprise elastic air chambers using several differently designed valves, several springs and a major number of parts and arrangements for the separation of contacts. But a disadvantage of such switch is that the acceleration of the separation of the contacts is at an insufiicient rate. It is also known to provide a pneumatically delayed push button switch with a great number of parts and complicated design. In such a construction, pot magnets are usually arranged in a housing about a guide piston which is hermetically sealed in the housing and terminates in an air chamber by means of a diaphragm. The guide piston carries a vent valve which closes the ventilation .by a compression spring in the control knob. The adjustable ventilation retarding valve is arranged in the bottom of the valve chamber. The lower part of the guide piston is arranged in an axially displaced guide pin which is actuated by a compression spring which moves a ring armature with a contact bridge. When the connected guide piston returns the spring expands and presses against the longitudinally displaceable guide pin. The spring actuated guide pin provided to move the ring armature is held by the permanent magnets until after a certain path of movement at which the force of the pre-stressed spring outweighs the magnetic force. Then the armature is suddenly released. This arrangement effects a rapid withdrawal of the contacts, but it is very expensive. The pressure equalizing valve is only opened after the connecting operation is completed which may be tolerable with a short feed path but which requires a great switching force with longer feed paths.

An object of the present invention is to eliminate the inconveniences of the known time switches, particularly in respect to permitting a sudden separation of the contacts in an inexpensive manner. Another object of the invention is to obtain a prolonged delayed connection, for example half an hour or more, with the required time switch, and also to provide a connection for the time switch without great energy consumption.

In accordance with the invention there is provided a time switch construction which includes a bellows or other air sealed chamber which carries a slide control element or bridge which is movable with axial play against a control slide which forms a contact bridge connecting the terminals of the switch element. The construction is such that the contact bridge is locked against the force of a compression spring until a control element is returned after the escape of the air from the bellows. The control element for the slide is returned over a predetermined free distance before it moves the slide to open the lock and to permit the spring to suddenly force the The connection between the slide and the control element is eifected prefer- 3,33,297 Patented Feb. 7, 1967 ably by means of a carrier which engages in a recess of the slide or bridge such that, upon initial connection of the switch, the carrier urges the bridge into a set position at which it is locked by a resilient latching element. Thereafter the carrier moves with the control element upon the escape of the air from the bellows without the carrier contacting the bridge slide until it has moved to a predetermined distance at which it contacts the slide and moves it out of latching engagement with the latch element. The latch for the sliding bridge member is formed, according to the invention, by a ratchet part with an inclined contact face which is connected with the switch housing and protrudes into a recess of the bridge and is engaged over a cammed surface thereof. The latch may advantageously include a leaf spring element having an angular portion which engages around the cammed surface of the contact slide. The device further advantageously includes a pressure piece or control rod element for opening the pressure equalizing valve for regulating the air in the pressure chamber such as the bellows element. The escape of the air from the bellows is controlled by a throttle valve which may be adjusted by the setting of an adjustment screw to give the desired resetting time for the switch.

Accordingly, it is an object of this invention to provide an improved pneumatically operated switch having means for rapidly moving the contacts to a disconnect position after the setting time for the switch has expired.

A further object of the invention is to provide a switch which includes an inexpensive housing construction in which is mounted an expandable air chamber, such as a bellows, which is connected at one end to a slide member having a carrier which engages in a slot or recess of a contact slide or bridge member; and wherein the slide is locked in a set position at which the contacts electrically connect the two terminals of the switch element but which may be unlatched by the movement of the carrier member upon the escape of a predetermined quantity of fluid from the expandable chamber.

A further object of the invention is to provide a switch which is simple in design, rugged in construction, and economical to manufacture.

The various features of novelty with characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating ad vantages and specific objects attained by its use, reference should be had to the accompanying drawing in which there is illustrated and described a preferred embodiment of the invention.

The only figure of the drawing is a longitudinal sectional view of a pneumatically operated electrical time switch constructed in accordance with the invention.

Referring to the drawing in particular, the invention embodied therein comprises a switch housing 1 which includes a widened portion in which there is arranged an expansible fluid chamber such as an air bellows 2 which is sealed in an air tight manner with a rear wall 23 of the housing. The other side of the bellows 2 is connected to a control slide or movable member 30 having a regulating cylinder 3 projecting outwardly from the forward end in which is slidable a pressure piece or control rod '18. The pressure in the interior of the bellows 2 communicates through a bore 30a of the slide 30 and acts against a face of the pressure equalizing valve 5 in an intermediate piece 32 having a bore 32a in which an end portion of the valve 5 is slidable. The valve 5 is urged to a position closing the bore 32a by means of a compression spring 8. The valve 5 may be opened to permit a release of the air pressure within the bellows 2 by pressing down on a control knob 6 carried at the outer end of a pressure piece 18 to cause the pressure piece 18 to bear against the projecting portion of the valve and move it off its seat. The valve 5 tightly closes the bore 32a by pushing against a gasket 7 when the spring 8 is eifective.

In accordance with the invention, when the bellows 2 is fully charged with air to a predetermined amount, the control slide 3d is moved in a direction away from the rear wall 23 to compress a compression spring 15 within a narrow portion 1a of the housing 1. The control slide 3t} carries a carrier or projecting element 9 which extends outwardly into a recess of a sliding switch element 11 which is slidable within the housing 1.

In the position indicated, terminals 13 and 14 are electrically connected within the switch by means of a con tact bridge 1% having button elements a which are wedged into contact with conductive connections 33 and 34 of the terminals 13 and 14, respectively. Recesses 36 and 353 are provided for accommodating the buttons in the non-contacting position or disconnect position. The sliding switch 11 is moved to the contacting position when the carrier 9 abuts against a face 11" to cause a cam surface 19 of the sliding switch 11 to engage over a latching element or leaf spring 12. In the engaged connected position, the latching element 12 moves up into a recess 21 defined in the sliding switch It.

The delayed disconnecting or resetting of the switch is eflfected by the compression spring 15 as the fluid is permitted to escape from the bellows 2 to cause the bellows to collapse as the fluid is moved out. For this purpose, a throttle valve 16 is provided on the wall 23 and air may escape through a bore at which there is positioned an adjusting screw which acts against a gasket 22. The adjusting screw 20 may 'be set so that the air may slowly escape through the bore and around the gasket 22, to permit the delayed return of the control slide 30. During the delayed return of the control slide the carrier 9 moves away from the surface 11 to the surface 11 on the sliding switch 11 before it pulls the latter out ofits latched position to release the latching element 12 from the cam surface 19.

When the cam surface 19 is released, a compression spring 17 which has been pre-stressed by abutment against an end of the housing when it is compressed within a recess of the sliding switch 11, will cause the rapid acceleration of the switch 11 to the left after the unlatching occurs so that sparking of the contacts will be pre vented.

The switch of the present invention is particularly desirable for use, for example, with an auxiliary heater in a motor vehicle. The switch may be employed for ensuring that the heater will be shut ofl when the driver forgets to disconnect the heater after leaving the vehicle. A time switch of this nature may be operated, for example, very satisfactorily with a time delay of about half an hour.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A time switch comprising a member defining a fluid pressure chamber which is expandable and contractible in accordance with the fluid pressure therein, valve means associateed with said fluid pressure chamber for permitting the escape of fluid from said pressure chamber, a slide control member connected to said member and movable in one direction upon expansion of said member and in another direction upon contraction of said member, first and second fixed spaced contacts adjacent said slide control member, a sliding contact bridge adjacent said control member and said fixed spaced contacts and having contact portions engageable with respect to said first and second contacts and having a side with a recess adjacent said control member, means located adjacent said bridge to bias said bridge in a direction out of contact engagement located adjacent said bridge when said bridge is in a contact-making engaged position, means to latch said bridge in a contact-making engaged position against the force of said biasing means to position the contact portions of said bridge in engagement with said first and second fixed contacts, said slide control having a carrier portion extending into the recess of said bridge, said carrier portion being movable along the recess of said bridge and being engageable with said bridge adjacent one edge of said recess to move said bridge into an operative position and into latching engagement with said latching means, said bellows being contractible upon escape of fluid from said pressure chamber to move said carrier first along the recess of said bridge member without contacting said bridge member and thereafter into contact with the bridge member adjacent the opposite edge of said recess to move said bridge member out of engagement with said latching means, said biasing means being thereafter effective to rapidly move said bridge member to a position bringing said contact portions out of engagement with said first and second fixed contacts.

2. A time switch comprising a member defining a fluid pressure chamber which is expandable and contractible in accordance with the fluid pressure the-rein, valve means associated with said fluid pressure chamber for permitting the escape of fluid from said pressure chamber, a slide control member connected to said memher and movable in one direction upon expansion of said member and in another direction upon contraction of said member, first and second fixed spaced contacts adjacent said slide control member, a sliding contact bridge adjacent said control member and said fixed spaced con tacts and having contact portions engageable with respect to said first and second contacts and having a side with a recess adjacent said control member, means to bias said bridge in a direction out of contact engagement when said bridge is in a contact-making engaged position, means to latch said bridge in a contact-making engaged position against the force of said biasing means to position the contact portions of said bridge in engagement With said first and second fixed contacts, said slide control having a carrier portion extending into the recess of said bridge, said carrier portion being movable along the recess of said bridge and being engageable with said bridge adjacent one edge of said recess to move said bridge into an operative position and into latching engagement with said latching means, said bellows being contractible upon escape of fluid from said pressure chamber to move said carrier first along the recess of said bridge member without contacting said bridge member and thereafter into contact with the bridge member adjacent the opposite edge of said recess to move said bridge member out of engagement with said latching means, said biasing means being thereafter effective to rapidly move said bridge member to a position bringing said contact portions out of engagement with said first and second fixed contacts, said slide control member hav ing a bore therein with equalizing valve means in said bore for equalizing the pressure in said member.

3. A time switch comprising a member defining a fluid pressure chamber which is expandable and contractible in accordance with the fluid pressure therein, valve means associated with said fluid pressure chamber for permitting the escape of fluid from said pressure chamber, a slide control member connected to said member and movable in one direction upon expansion of said member and in another direction upon contraction of said member, first and second fixed spaced contacts adjacent said slide control member, a sliding contact bridge adjacent said control member and said fixed spaced contacts and having contact portions engageable with respect to said first and second contacts and having a side with a recess adjacent said control member, means to bias said bridge in a direction out of contact engagement located adjacent said bridge when said bridge is in a contact-making engaged position, means to latch said bridge in a contactmaking engaged position against the force of said biasing means to position the contact portions of said bridge in engagement with said first and second fixed contacts, said slide control having a carrier portion extending into the recess of said bridge, said carrier portion being movable along the recess of said bridge and being engageable with said bridge adjacent one edge of said recess to move said bridge into an operative position and into latching engagement with said latching means, said bellows being contractible upon escape of fluid from said pressure chamber to move said carrier first along the recess of said bridge member without contacting said bridge member and thereafter into contact with the bridge member adjacent the opposite edge of said recess to move said bridge member out of engagement with said latching means, said biasing means being thereafter effective to rapidly move said bridge member to a position bringing said contact portions out of engagement with said first and second fixed contacts, said member comprising a bellows, a housing, said bellows being in said housing, and end Wall of said housing closing one end of said bellows.

4. A time switch comprising a housing, a bellows in said housing sealed against one wall thereof, adjustable valve means in the wall sealing said bellows communicating with the interior of said bellows for permitting the escape therefrom, spring means in said housing urging said bellows to a collapsed position, said bellows being expandable against the force of said spring means upon an increase of fluid pressure therein, a slide control member connected to said member and movable in one direction upon expansion of said member and in another direction upon contraction of said member, first and second fixed spaced contacts adjacent said slide control member, a sliding contact bridge adjacent said control member and said fixed spaced contacts and having contact portions engageable with respect to said first and second contacts and having a side with a recess adjacent said control member, means to bias said bridge in a direction out of contact engagement when said bridge is in acontact-making engaged position, and means located adjacent said bridge to latch said bridge in a contact-making engaged position against the force of said biasing means to position the contact portions of said bridge in engagement with said first and second fixed contacts, said slide control having a carrier portion extending into the recess of said bridge, said carrier portion being movable along the recess of said bridge and being engageable with said bridge adjacent one edge of said recess to move said bridge into an operative position and into latching engagement with said latching means, said bellows being contractible upon escape of fluid from said pressure chamber to move said carrier first along the recess of said bridge member without contacting said bridge mem' ber and thereafter into contact with the bridge member adjacent the opposite edge of said recess to move said bridge member out of engagement with said latching means, said biasing means being thereafter effective to rapidly move said bridge member to a position bringing said contact portions out of engagement with said first and second fixed contacts.

5. A time switch comprising a member defining a fluid pressure chamber which is expandable and contractible in accordance with the fluid pressure therein, valve means associated with said fluid pressure chamber for permitting the escape of fluid from said pressure chamber, a slide control member connected to said member and movable in one direction upon expansion of said member and in another direction upon contraction of said member, first and second fixed spaced contacts adjacent said slide control member, a sliding contact bridge adjacent said control member and said fixed spaced contacts and having contact portions engageable with respect to said first and second contacts and having a side with a recess adjacent said control member, means to bias said bridge in a direction out of contact engagement when said bridge is in a contact-making engaged position, means located adjacent said bridge to latch said bridge in a contact-making engaged position against the force of said biasing means to position the contact portions of said bridge in engagement with said first and second fixed contacts, said slide control having a carrier portion extending into the recess of said bridge, said carrier portion being movable along the recess of said bridge and being engageable with said bridge adjacent one edge of said recess to move said bridge into an operative position and into latching engagement with said latching means, said bellows being contractible upon escape of fluid from said pressure chamber to move said carrier first along the recess of said bridge member without contacting said bridge member and thereafter into contact with the bridge member adjacent the opposite edge of said recess to move said bridge member out of engagement with said latching means, said biasing means being thereafter effective to rapidly move said bridge member to a position bringing said contact portions out of engagement with said first and second fixed contacts, said slide control member having a bore therein with equalizing valve means in said bore for equalizing the pressure in said member, means connecting said slide control member and said bridge together for combined movement in each direction after an initial delay of the movement of said bridge member after movement of said slide member has been initiated.

6. A time switch comprising a member defining a fluid pressure chamber which is expandable and contractible in accordance with the fluid pressure therein, valve means associated with said fluid pressure chamber for permitting the escape of fluid from said pressure chamber, a slide control member connected to said member and movable in one direction upon expansion of said member and in another direction upon contraction of said member, first and second fixed spaced contacts adjacent said slide control member, a sliding contact bridge adjacent said control member and said fixed spaced contacts and having con tact portions engageable with respect to said first and second contacts and having a side with a recess adjacent said control member, means to bias said bridge in a direction out of contact engagement when said bridge is in a contact engaging position, means located adjacent said bridge to latch said bridge in a contact-making engaged position against the force of said biasing means to position the contact portions of said bridge in engagement with said first and second fixed contacts, said slide control having a carrier portion extending into the recess of said bridge, said carrier portion being movable along the recess of said bridge and being engageable with said bridge adjacent one edge of said recess to move said bridge into an operative position and into latching engagement with said latching means, said bellows being contractible upon escape of fluid from said pressure chamber to move said carrier first along the recess of said bridge member without contacting said bridge member and thereafter into contact with the bridge member adjacent the opposite edge of said recess to move said bridge member out of engagement with said latching means, said biasing means being thereafter effective to rapidly move said bridge member to a position bringing said contact portions out of engagement with said first and second fixed contacts, said slide control member having a bore therein with equalizing valve means in said bore for equalizing the pressure in said member, said latching means comprising a leaf spring having a ratchet portion, said bridge having a detent en gageable around the latching portion of said leaf spring.

7. A time switch according to claim 6 wherein said leaf spring is of angular configuration and has an arm secured to said housing, the opposite arm of said leaf spring including an inclined surface adapted to engage a similar surface of said bridge.

8. A time switch comprising a member defining a fluid pressure chamber which is expandable and contractible in accordance with the fluid pressure therein, valve means associated with said fluid pressure chamber for permitting the escape of fluid from said pressure chamber, a slide control member connected to said member and movable in one direction upon expansion of said member and in another direction upon contraction of said member, first and second fixed spaced contacts adjacent said slide control member, a sliding contact bridge adjacent said control member and said fixed spaced contacts and having contact portions engageable with respect to said first and second contacts and having a side with a recess adjacent said control member, means to bias said bridge in a direction out of contact engagement when said bridge is in a contact-making engaged position, means located adjacent said bridge to latch said bridge in a contact-making engaged position against the force of said biasing means to position the contact portions of said bridge in engagement with said first and second fixed contacts, said slide control having a carrier portion extending into the recess of said bridge, said carrier portion being movable along the recess of said bridge and being engageable with said bridge adjacent one edge of said recess to move said bridge into an operative position and into latching engagement with said latching means, said bellows being contractible upon escape of fluid from said pressure chamber to move said carrier first along the recess of said bridge member Without contacting said bridge member and thereafter into contact with the bridge member adjacent the opposite edge of said recess to move said bridge member out of engagement with'said latching means, said biasing means being thereafter effective to rapidly move said bridge member to a position bringing said contact portions out of engagement with said first and second fixed contacts, said slide control member having a bore therein with equalizing valve means in said bore for equalizing the pressure in said member, said slide control member having a bore defined therethrough in communication at one end with said bellows, and a control piece slidable into the opposite end of said bore, equalizing valve means defined in said bore, including means biasing a valve member to close said bore, said pressure piece being movable to displace said valve to open the bore.

9. A time switch comprising a member defining a fluid pressure chamber which is expandable and contractible in accordance with the fluid pressure therein, valve means associated with said fluid pressure chamber for permitting the escape of fluid from said pressure chamber, a slide control member connected to said member and movable in one direction upon expansion of said member and in another direction upon contraction of said member, first and second fixed spaced contacts adjacent said slide control member, a sliding contact bridge adjacent said control member and said fixed spaced contacts and having contact portions engageable with respect to said first and second contacts and having a side with a recess adjacent said control member, means adjacent said bridge to bias said bridge in a direction out of contact engagement when said bridge is in a contact-making engaged position, means to latch said bridge located adjacent said bridge in a contact-making engaged position against the force of said biasing means to position the contact portions of said bridge in engagement with said first and second fixed contacts, said slide control having a carrier portion extending into the recess of said bridge, said carrier portion being movable along the recess of said bridge and being engageable with said bridge adjacent one edge of said recess to move said bridge into an operative position and into latching engagement with said latching means, said bellows being contractible upon escape of fluid from said pressure chamber to move said carrier first along the recess of said bridge member without contacting said bridge member and thereafter into contact with the bridge member adjacent the opposite edge of said recess to move said bridge member out of engagement with said latching means, said biasing means being thereafter effective to rapidly move said bridge member to a position bringing said contact portions out of engagement with said first and second fixed contacts, said slide control member having a bore therein with equalizing valve means in said bore for equalizing the pressure in said member, said valve means for permitting the escape of fluid from said chamber comprising a threaded bore, a gasket surrounding the exterior of said bore and an adjustment screw member threaded into said bore and bearing against said gasket for varying the holding pressure thereon.

References Cited by the Examiner UNITED STATES PATENTS 2/1953 Baumheekcl 200-34 9/1961 Webb 200-34 

1. A TIME SWITCH COMPRISING A MEMBER DEFINING A FLUID PRESSURE CHAMBER WHICH IS EXPANDABLE AND CONTRACTIBLE IN ACCORDANCE WITH THE FLUID PRESSURE THEREIN, VALVE MEANS ASSOCIATED WITH SAID FLUID PRESSURE CHAMBER FOR PERMITTING THE ESCAPE OF FLUID FROM SAID PRESSURE CHAMBER, A SLIDE CONTROL MEMBER CONNECTED TO SAID MEMBER AND MOVABLE IN ONE DIRECTION UPON EXPANSION OF SAID MEMBER AND IN ANOTHER DIRECTION UPON CONTRACTION OF SAID MEMBER, FIRST AND SECOND FIXED SPACED CONTACTS ADJACENT SAID SLIDE CONTROL MEMBER, A SLIDING CONTACT BRIDGE ADJACENT SAID CONTROL MEMBER AND SAID FIXED SPACED CONTACTS AND HAVING CONTACT PORTIONS ENGAGEABLE WITH RESPECT TO SAID FIRST AND SECOND CONTACTS AND HAVING A SIDE WITH A RECESS ADJACENT SAID CONTROL MEMBER, MEANS LOCATED ADJACENT SAID BRIDGE TO BIAS SAID BRIDGE IN A DIRECTION OUT OF CONTACT ENGAGEMENT LOCATED ADJACENT SAID BRIDGE WHEN SAID BRIDGE IS IN A CONTACT-MAKING ENGAGED POSITION, MEANS TO LATCH SAID BRIDGE IN A CONTACT-MAKING ENGAGED POSITION AGAINST THE FORCE OF SAID BIASING MEANS TO POSITION THE CONTACT PORTIONS OF SAID BRIDGE IN ENGAGEMENT WITH SAID FIRST AND SECOND FIXED CONTACTS, SAID SLIDE CONTROL HAVING A CARRIER PORTION EXTENDING INTO THE RECESS OF SAID BRIDGE, SAID CARRIER PORTION BEING MOVABLE ALONG THE RECESS OF SAID BRIDGE AND BEING ENGAGEABLE WITH SAID BRIDGE ADJACENT ONE EDGE OF SAID RECESS TO MOVE SAID BRIDGE INTO AN OPERATIVE POSITION AND INTO LATCHING ENGAGEMENT WITH SAID LATCHING MEANS, SAID BELLOWS BEING CONTRACTIBLE UPON ESCAPE OF FLUID FROM SAID PRESSURE CHAMBER TO MOVE SAID CARRIER FIRST ALONG THE RECESS OF SAID BRIDGE MEMBER WITHOUT CONTACTING SAID BRIDGE MEMBER AND THEREAFTER INTO CONTACT WITH THE BRIDGE MEMBER ADJACENT THE OPPOSITE EDGE OF SAID RECESS TO MOVE SAID BRIDGE MEMBER OUT OF ENGAGEMENT WITH SAID LATCHING MEANS, SAID BIASING MEANS BEING THEREAFTER EFFECTIVE TO RAPIDLY MOVE SAID BRIDGE MEMBER TO A POSITION BRINGING SAID CONTACT PORTIONS OUT OF ENGAGEMENT WITH SAID FIRST AND SECOND FIXED CONTACTS. 